This invention relates generally to an irrigation system to be used during surgery and, more particularly, to an irrigation and vacuum system for use in conjunction with endoscopic or minimally invasive surgery.
Laparoscopic surgery was first performed in France in 1987 and in the United States in 1988. Since that time laparoscopic surgery, also known as minimally invasive or endoscopic surgery, has grown at a phenomenal rate. Many procedures that previously used open surgery techniques are now done using a laparoscopic approach.
While laparoscopic surgery initially developed with the removal of gall stones, laparoscopic surgery is now used for many other surgical procedures including hernia repair, appendectomy, pediatric, gynecological, genitourinary, bowel, colorectal, gastroduodenal, and vascular surgery, just to name some examples. Laparoscopic or minimally invasive surgery is the latest rage in new surgery techniques. By use of laparoscopic surgery, infection and trauma for the patient is reduced. The patients are able to go home much earlier and have much less effect from the surgery. The pain and suffering normally associated with surgery is greatly reduced. Laparoscopic surgery is truly the wave of the future in surgical techniques.
In normal laparoscopic surgery, a trocar and cannula are inserted through the esophagus, around muscle and other tissue, and into a body cavity where the surgeon is to perform the surgical procedure. As the surgical procedure is being performed, it is necessary to remove the fluids from the body cavity that may interfere with the ability to physically see what is occurring. As would occur in open surgery, laparoscopic surgery needs to provide irrigation to the area where the procedure is being performed and suctioning to remove the irrigation fluid as well as the body fluids that interfere with the ability to visually see what is occurring.
Using an appendectomy as an example of the surgery that is being performed laparoscopically, typically there would be (a) a puncture for the endoscope, (b) a puncture for the appendix extractor, and (c) a puncture for the insertion of the surgical instruments. It is necessary for the surgeon to be able to see through the endoscope what is occurring in the body cavity. The providing of irrigation fluids to the body cavity and the removal of those fluids is necessary for the successful performance of the appendectomy.
In the past, irrigation is normally provided through a trumpet valve via one of the punctures to the body cavity. The trumpet valve is connected to a source of (a) saline solution for irrigation purposes and (b) vacuum for extraction of the irrigation fluid and body fluids. Depending upon which portion of the trumpet valve is pushed, either irrigation or vacuum is provided. However, during long periods of non-use, neither irrigation nor vacuum will be provided to the patient.
Typically, the irrigation fluid is provided under pressure by means of a pump to the trumpet valve. It is important to the surgeon to have pressurized irrigation fluid immediately available with essentially no delay upon pushing the trumpet valve. The surgeon does not want to have to reach and flip other switches, such as hand or foot switches, or push other buttons other than pushing the trumpet valve itself. In other words, the surgeon wants to push one button on the trumpet valve to provide irrigation fluid and push another button on the trumpet valve to remove the irrigation fluid and body fluids. When neither are pushed, neither irrigation fluid nor a vacuum are being provided to the body cavity of the patient. The surgeon wants either irrigation fluid or vacuum to be available instantaneously upon demand. Moreover, providing a separate switch has the additional disadvantage of increased controls and complexity of the system plus additional expense.
In the past, pumps that would provide the irrigation fluid would have to be switched ON to provide the fluid and then turned OFF. When the pump was switched ON, there would be a delay of several seconds before the irrigation fluids are provided under pressure. This delay is disadvantageous and unacceptable to the surgeons. To avoid the foregoing disadvantage, the pump could be designed to run continuously. However, if the pump is left ON continuously and no fluids are flowing so the pump is operating in a xe2x80x9cdeadheadxe2x80x9d condition, the pump has a tendency to overheat as it constantly rotates at a relatively high speed without the fluids flowing through the pump which provide cooling for the pump. Excessive heating of the pump affects the reliability of the pump, can cause hot fluid to be supplied to the patient, and can even blow off the connections as pressure builds. Therefore, in systems with continuously running pumps, some type of external cooling must be provided for the pump, which is a problem when performing laparoscopic surgery.
Consequently, it would be advantageous to provide a system which can supply irrigation instantaneously on demand without requiring a separate ON/OFF switch and without resulting in overheating of the pump. Also in the past, a tremendous expense incurred in laparoscopic surgery is the replacement of the entire system between procedures. Normally after a laparoscopic surgery technique is performed on one patient, the entire irrigation system (including the pump and all valving associated therewith) is thrown away and replaced with a new laparoscopic irrigation system before a new procedure is performed on a new patient.
The motor portion of the pump, including the windings and coils, is fairly expensive. If the windings and coils portion of the pump can be reused, this could save a considerable amount of money. The irrigation fluid itself is sterile and does not contaminate the pump. If backflow from the trumpet valve is prevented, it may be possible to reuse either a portion or even the entire pump. By the present invention, it is found that a portion of the pump can be replaced and still save the major expense that may be incurred by replacing the entire pump.
The present invention overcomes the foregoing disadvantages by providing a pump that can be switched from one operating condition to another operating condition and still not be turned OFF. By switching to a second operating condition, the pump can be ready to instantaneously deliver irrigation fluid under pressure and still avoid the problem of overheating as will be discussed further hereinbelow in conjunction with the present invention.
In endoscopic surgery, such as laparoscopic surgery which is provided through the abdomen, a saline solution is normally provided through a trumpet valve and a cannula into a cavity of the patient""s body. The saline solution is pumped by a positive pressure pump. By pushing one button on the trumpet valve, the saline solution is pumped from the pump into the cavity of the patient""s body. By releasing the first button on the trumpet valve and pushing the second button, the same cannula is now connected to a source of vacuum. The source of vacuum will suck the saline solution and any body fluids at the end of the tube in the cavity of the patient""s body back toward the vacuum source with the fluids being collected in a vacuum cannister.
So that the entire system does not have to be thrown away when switching from patient to patient, the pump has been made partially disposable. The head of the pump that includes the impellers is made from a medical grade, yet disposable, plastic. By a simple hand twisting action, the head of the pump is connected to the body of the pump. The body of the pump may be used repeatedly.
Because the pump normally operates at 12 volts DC, if it continues to operate at that voltage at a no-load or deadhead condition, the pump will overheat. To eliminate the problem of overheating, if fluid does not flow through the pump for a predetermined time, the voltage being applied to the pump will be reduced. The reduced voltage reduces the speed of the pump and hence the friction created by the impellers continuing to circulate the fluid in a deadhead condition. This reduced speed reduces almost exponentially the amount of heat being generated by the pump. Therefore, at the reduced voltage, the pump does not create excess heat, but at the same time maintains saline solution under pressure at the trumpet valve ready for instantaneous delivery to the patient if requested by the surgeon. A timing circuit is provided in the controls for the voltage source. After a predetermined time interval during which no fluids have been requested, the pump will automatically switch to a lower voltage.
To make the electronics portion of the power supply failsafe, an override or xe2x80x9ccrowbarxe2x80x9d circuit is included. The override circuit automatically reduces the voltage being applied to the pump if the first time interval, plus an additional time interval has passed and the voltage of the pump has not been reduced. The additional timing circuit, or crowbar circuit, overrides the prior electronic controls for the power supply to reduce the voltage being applied to the pump.
As a safety when the disposable portion is reused, additional check valves may be included to prevent backflow from the trumpet valve back to the head of the pump. By simply replacing the check valve and the downstream hoses, the disposable head of the pump could be used a few times without danger of infection.
The timing portion of the circuit is simply used to reduce the voltage being applied to the motor during periods of non-use and, hence, the speed of the motor after a period of nonuse of the motor to deliver an irrigation solution to the patient. A failsafe circuit is included in the event of a failure by the electronics.